1. Technical Field
The present invention relates to a worm biasing structure.
2. Related Art
A rotating force of a motor for assistance generating an assisting force is generally transmitted to a pinion shaft and so on through a speed reduction mechanism in a motor-driven power steering apparatus. The speed reduction mechanism includes, for example, a worm gear mechanism and so on.
When the motor-driven power steering apparatus is, for example, a pinion-assist type apparatus, the speed reduction mechanism includes a worm connected to an output shaft of a motor and a worm wheel engaged with the worm and fixed to the pinion shaft. In Patent Literature 1 (JP-A-2013-208932), the worm is biased toward the worm wheel by a spring force of one kind of compression coil spring so that the worm is engaged with the worm wheel in good condition and for preventing backlash between the worm and the worm wheel even when the worm and/or the worm wheel are worn out.